482 research outputs found

    Activation of clay sample from Zaria L.G.A. of kaduna State and testing its bleaching performance on groundnut oil, palm oil and cottenseed oil

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    Clay samples from Zaria L.G.A. of Kaduna state was acid activated using hydrochloric acid in the concentration range of 5%, 10%, to 30% (v/v), at 90oC Β± 2oC for 3 hours, and heat activated at 145oC for 30 minutes. The raw, acid and heat activated clay were tested on groundnut, palm and cottonseed oils. The per cent colour reduction was monitored spectrophotometrically. There was improvement in the decolourizing performance of the clay sample when acid or heat activated towards the three oil samples, but acid activation is more suitable for groundnut oil, while for palm and cottonseed oils the results obtained were similar for both methods.Β Keywords: Clay, Kaolinite, Bleaching, Zaria, Oi

    Screening of conditions controlling spectrophotometric sequential injection analysis

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    <p>Abstract</p> <p>Background</p> <p>Despite its potential benefits over univariate, chemometrics is rarely utilized for optimizing sequential injection analysis (SIA) methods. Specifically, in previous vis-spectrophotometric SIA methods, chemometrically optimized conditions were confined within flow rate and reagent concentrations while other conditions were ignored.</p> <p>Results</p> <p>The current manuscript reports, for the first time, a comprehensive screening of conditions controlling vis-spectrophotometric SIA. A new diclofenac assay method was adopted. The method was based on oxidizing diclofenac by permanganate (a major reagent) with sulfuric acid (a minor reagent). The reaction produced a spectrophotometrically detectable diclofenac form. The 2<sup>6 </sup>full-factorial design was utilized to study the effect of volumes of reagents and sample, in addition to flow rate and concentrations of reagents. The main effects and all interaction order effects on method performance, i.e. namely sensitivity, rapidity and reagent consumption, were determined. The method was validated and applied to pharmaceutical formulations (tablets, injection and gel).</p> <p>Conclusions</p> <p>Despite 64 experiments those conducted in the current study were cumbersome, the results obtained would reduce effort and time when developing similar SIA methods in the future. It is recommended to critically optimize effective and interacting conditions using other such optimization tools as fractional-factorial design, response surface and simplex, rather than full-factorial design that used at an initial optimization stage. In vis-spectrophotometric SIA methods those involve developing reactions with two reagents (major and minor), conditions affecting method performance are in the following order: sample volume > flow rate β‰ˆ major reagent concentration >> major reagent volume β‰ˆ minor reagent concentration >> minor reagent volume.</p

    Isolation and Characterization of Stigmasterol and Bis-(5, 7-diacetyl-catechin-4’-Ξ±- rhamnopyranoside) from the Stem bark of Neocarya macrophylla (Sabine) Prance (Chrysobalanaceae)

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    Neocarya macrophylla belongs to the Chrysobalanaceae family and is extensively used in folk medicine as an antibacterial, antivenin, antiasthmatic, anticancer, analgesic and anti-inflammatory agent. This study was aimed at isolation and characterization of compounds from the stem bark of Neocarya macrophylla.Β  Pulverized plant material was exhaustively extracted with methanol using maceration method and concentrated invacuo with the aid of rotary evaporator at 40oC to afford a reddish brown crude methanol extract (ME). The methanol extract was successively partitioned into hexane, dichloromethane, ethylacetate, n-butanol and aqueous fractions. Stigmasterol was isolated from the hexane fraction and a catechin glycoside, Bis-(5,7-diacetyl-catechin-4’-Ξ±- rhamnopyranoside) wasΒ  isolated from the ethylacetate soluble fraction using a combination of silica gel column, gel filtration (sephadex LH-20) and preparative thin layer chromatography. The structures of the compounds were established on the basis of chemical tests, spectroscopic analysis and by comparison with reference spectral data.Keywords: Neocarya macrophylla, phytochemical, stigmasterol, Bis-(5, 7-diacetyl-catechin-4’-Ξ±-rhamnopyranoside)

    Pengaruh Kepatuhan Suplementasi Tablet Kalsium Modifikasi terhadap Kadar Kalsium dan Tekanan Darah Pada Ibu Hamil

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    A low intake of calcium leads to an increase in high blood pressure byΒ stimulating the release of paratiroid and renin hormones that lead to increase inΒ intracellular calcium concentration in the vasculer smooth muscle cells and resultΒ in vasocontriction. This study aims to determine the influence of compliance toΒ supply modified calcium tablet toward calcium level and blood pressure inΒ pregnant mothers. This research was conducted at RSIA Sitti Khadijah IΒ Maternity Hospital Makassar with research design of quasy experiment with prepost test group control design. There were 30 pregnant mother sampels ofΒ prehypertension in gestational age> 20 weeks, 12 pregnant women were givenΒ normal calcium tablets and 18 pregnant women given modified calcium tabletsΒ for 8 weeks each. Data analysis use paired t test. The results indicate that there isΒ a different changes of calcium level and blood pressure between pregnantΒ mothers of intervention group and control group with the value of p = 0.000Β (p<0.05). After intervention averagely the calcium level increase in interventionΒ group 0.4 mg/dl while in control group 0.1 mg/dl, followed by the averageΒ decrease in blood pressure of systole and dyastole in the intervention groupΒ 15.4/9.6 mmHg while in the control group 3.5/4.5 mmHg

    The Impact of Gate-Induced Drain Leakage (GIDL) on Scaled MOSFETs for Low Power Device

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    In this research, we investigated the impact of Gate-Induced Drain Leakage (GIDL) on scaled Metal-OxideSemiconductor Field-Effect Transistor (MOSFET) for low power application. The output of this research determined the implications of GIDL on the performance of MOSFET with various sizes that are supplied via low voltage power. The MOSFET design parameters were proposed by referring to the International Technology Roadmap for Semiconductors (ITRS), 2011 edition. SILVACO’s DEVEDIT and ATLAS software was used for this research to design a device structure and obtain output characteristics. Three MOSFETs with different physical gate length and several other parameters were designed and simulated. From the extracted data, it shows that as the size of MOSFET physical gate length become smaller, the leakage current tends to be higher. Apart from GIDL current (IGIDL) value, the β€œON” current (ION) value and threshold voltage (VTH) value also been extracted for all MOSFET designs

    Molecular diversity of Cotton leaf curl Gezira virus isolates and their satellite DNAs associated with okra leaf curl disease in Burkina Faso

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    Okra leaf curl disease (OLCD) is a major constraint on okra (Abelmoschus esculentus) production and is widespread in Africa. Using a large number of samples representative of the major growing regions in Burkina Faso (BF), we show that the disease is associated with a monopartite begomovirus and satellite DNA complexes. Twenty-three complete genomic sequences of Cotton leaf curl Gezira virus (CLCuGV) isolates associated with OLCD, sharing 95 to 99% nucleotide identity, were cloned and sequenced. Six betasatellite and four alphasatellite (DNA-1) molecules were also characterized. The six isolates of betasatellite associated with CLCuGV isolates correspond to Cotton leaf curl Gezira betasatellite (CLCuGB) (88 to 98% nucleotide identity). One isolate of alphasatellite is a variant of Cotton leaf curl Gezira alphasatellite (CLCuGA) (89% nucleotide identity), whereas the three others isolates appear to correspond to a new species of alphasatellite (CLCuGA most similar sequence present 52 to 60% nucleotide identity), provisionally named Okra leaf curl Burkina Faso alphasatellite (OLCBFA). Recombination analysis of the viruses demonstrated the interspecies recombinant origin of all CLCuGV isolates, with parents being close to Hollyhock leaf crumple virus (AY036009) and Tomato leaf curl Diana virus (AM701765). Combined with the presence of satellites DNA, these results highlight the complexity of begomoviruses associated with OLCD

    The Merging of Two Dynastiesβ€”Identification of an African Cotton Leaf Curl Disease-Associated Begomovirus with Cotton in Pakistan

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    Cotton leaf curl disease (CLCuD) is a severe disease of cotton that occurs in Africa and Pakistan/northwestern India. The disease is caused by begomoviruses in association with specific betasatellites that differ between Africa and Asia. During survey of symptomatic cotton in Sindh (southern Pakistan) Cotton leaf curl Gezira virus (CLCuGV), the begomovirus associated with CLCuD in Africa, was identified. However, the cognate African betasatellite (Cotton leaf curl Gezira betasatellite) was not found. Instead, two Asian betasatellites, the CLCuD-associated Cotton leaf curl Multan betasatellite (CLCuMB) and Chilli leaf curl betasatellite (ChLCB) were identified. Inoculation of the experimental plant species Nicotiana benthamiana showed that CLCuGV was competent to maintain both CLCuMB and ChLCB. Interestingly, the enations typical of CLCuD were only induced by CLCuGV in the presence of CLCuMB. Also in infections involving both CLCuMB and ChLCB the enations typical of CLCuMB were less evident. This is the first time an African begomovirus has been identified on the Indian sub-continent, highlight the growing threat of begomoviruses and particularly the threat of CLCuD causing viruses to cotton cultivation in the rest of the world

    A Critical Assessment of the Effects of Bt Transgenic Plants on Parasitoids

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    The ecological safety of transgenic insecticidal plants expressing crystal proteins (Cry toxins) from the bacterium Bacillus thuringiensis (Bt) continues to be debated. Much of the debate has focused on nontarget organisms, especially predators and parasitoids that help control populations of pest insects in many crops. Although many studies have been conducted on predators, few reports have examined parasitoids but some of them have reported negative impacts. None of the previous reports were able to clearly characterize the cause of the negative impact. In order to provide a critical assessment, we used a novel paradigm consisting of a strain of the insect pest, Plutella xylostella (herbivore), resistant to Cry1C and allowed it to feed on Bt plants and then become parasitized by Diadegma insulare, an important endoparasitoid of P. xylostella. Our results indicated that the parasitoid was exposed to a biologically active form of the Cy1C protein while in the host but was not harmed by such exposure. Parallel studies conducted with several commonly used insecticides indicated they significantly reduced parasitism rates on strains of P. xylostella resistant to these insecticides. These results provide the first clear evidence of the lack of hazard to a parasitoid by a Bt plant, compared to traditional insecticides, and describe a test to rigorously evaluate the risks Bt plants pose to predators and parasitoids

    Exploring the Diversity of Plant DNA Viruses and Their Satellites Using Vector-Enabled Metagenomics on Whiteflies

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    Current knowledge of plant virus diversity is biased towards agents of visible and economically important diseases. Less is known about viruses that have not caused major diseases in crops, or viruses from native vegetation, which are a reservoir of biodiversity that can contribute to viral emergence. Discovery of these plant viruses is hindered by the traditional approach of sampling individual symptomatic plants. Since many damaging plant viruses are transmitted by insect vectors, we have developed β€œvector-enabled metagenomics” (VEM) to investigate the diversity of plant viruses. VEM involves sampling of insect vectors (in this case, whiteflies) from plants, followed by purification of viral particles and metagenomic sequencing. The VEM approach exploits the natural ability of highly mobile adult whiteflies to integrate viruses from many plants over time and space, and leverages the capability of metagenomics for discovering novel viruses. This study utilized VEM to describe the DNA viral community from whiteflies (Bemisia tabaci) collected from two important agricultural regions in Florida, USA. VEM successfully characterized the active and abundant viruses that produce disease symptoms in crops, as well as the less abundant viruses infecting adjacent native vegetation. PCR assays designed from the metagenomic sequences enabled the complete sequencing of four novel begomovirus genome components, as well as the first discovery of plant virus satellites in North America. One of the novel begomoviruses was subsequently identified in symptomatic Chenopodium ambrosiodes from the same field site, validating VEM as an effective method for proactive monitoring of plant viruses without a priori knowledge of the pathogens. This study demonstrates the power of VEM for describing the circulating viral community in a given region, which will enhance our understanding of plant viral diversity, and facilitate emerging plant virus surveillance and management of viral diseases
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